code: def rnd_history_date_days(max_days=30, last_dt=None):
      if last_dt is None:
          last_dt = pd.Timestamp.utcnow()
  
      days = randint(0, max_days)
  
      return last_dt - timedelta(days=days)
  
file_path: catalyst/tests/exchange/test_utils.py
imports: import os
  import tempfile
  from datetime import timedelta
  from random import randint
  import pandas
  from catalyst.assets._assets import TradingPair
  from catalyst.utils.paths import ensure_directory
label_desc: Use image node_id 1 for calling a global function with example usage: rnd_history_date_days(max_days, last_dt) and returns: unknown